You cannot choose DTL-H75004 in v3.0 version, model name change is locked. You can choose between various regions.
In the last available release there is no NTSC video forcing on Deckard. On Deckard models video mode will be applied according to region that you choose in the mechapwn.
https://github.com/MechaResearch/MechaPwn/releases/tag/3.00-rc4
Yes I readed it, so speedyes must be using rc3. Btw also in rc3 you could choose the region, for example europe but the video (on OSDSYS) will be forced to NTSC for ps1 games from any region to work.
Out of curiosity I was trying to understand what's the difference between your NTSC video-output forcing and FMCB video-output setting.